The purpose of this supplemental request is to permit the expansion of the present investigations of normal and experimentally obese monkeys, ages 3-8 years, to a group of spontaneously obese monkeys ages 13-23 and their age matched controls. In addition, two hypothalamically obese and two spontaneously obese-diabetic animals will be studied. The objectives remain as described in the "parent" proposal. The nature of the metabolic and hormonal signals involved in the control of ingestive behavior will be studied. Circulating hormones and metabolites, adipose tissue mass, gastrointestinal motility, and feeding behavior will be studied over five periods during the induction and remission of obesity: a) at normal body weight during normal feeding, b) during a period of intragastric overfeeding and progressive rapidly increasing body weight and adiposity, c) when obesity has been established and is being sustained by continued forced feeding, d) during the period of voluntary abstinence from food while body weight is decreasing toward normal, and e) in the period following stabilizing of body weight and the return of normal feeding. Under a) normal, b) experimentally obese, c) diabetic, and d) spontaneously obese conditions, experiments will be conducted to further define the nature and mechanisms of a newly described phenomenon of sustained oscillations in plasma levels of insulin, glucagon, and certain metabolites. These experiments will provide further data concerning the controls of the endocrine pancreas and feeding behavior. Results will contribute to the understanding of disturbances of feeding behavior and body weight, as well as the regulation of metabolism, and will have implications for the possible prevention or therapeutic management of obesity.